Event-based automated refereeing for robot soccer

The RoboCup Small Size League (SSL) is a robot soccer game with robots that play on a customized field with overhead cameras. The majority of the research effort to date has been on the performance of the autonomous teams in aspects of motion planning and team strategy. However, another critical component of a robot game is the referee. In current SSL games, refereeing is done by humans, who use a “referee box” that passes their calls to the robots. In this work, we contribute an automated referee (autoref) for SSL games, towards enabling games to proceed with little or no human supervision. The goal is to move closer to the eventual full automation of complete games with real robots. The technical challenges include the clear definition of the rules of the game in terms of features to be extracted from the visual perception, temporal sequencing, and corresponding calls and game management. We provide a description of a game of SSL as it is relevant to an autoref, by categorizing the rules of the game and presenting the structure of a game as a hybrid automaton. We then describe the complete autoref using a modular event-based architecture, following up on the automaton as a guideline, to keep track of the state of a game and issue referee commands accordingly. We present the results of using our autoref to referee games on real robots, as well as a comparison of the events detected by the autoref to the calls made by a human referee during the real SSL games at RoboCup 2014.